After looking for a program that would convert .wmv file I had on my computer (especially for Mac users) to any other format that I could then use in my I-Movie, I came across this website that actually says that you don't really need an extra converter and all you have to do is simply turn to your VLC player (which most of us probably already have on our computers) for help, as it can do it pretty much for you (it has its own stream/export function).
Its a simple procedure so just follow the following steps:
1. Launch VLC player
2. In the File menu of your player select "Streaming/ Exporting Wizard"
3. Select "Transcode/ Save to file" and click next
4. Click "Choose..." button and select .wmv extension file you need to convert
5. Select "Transcode video" and select the "H.264" codec and 1024 kb/s in a window below
6. Select "Transcode audio" and selected "MPEG 4 Audio" codec and 192 kb/s right in the small window below
7. Select "MPEG 4/ MP4" option as Encapsulation format
8. Click "Choose..." and save it as a "newfilename.mp4" to your desktop or designated folder
9. Then click finish and voila you are done. Converted file should appear shortly after either on your desktop or another folder.
I use MPEGStreamclip to convert other formats to .mov and you can download this program for free online.